System Modeling Using Matlab

Discussion in 'Programmer's Corner' started by herher, Jan 2, 2012.

  1. herher

    Thread Starter Member

    Oct 18, 2011
    53
    0
    Hi all the experts here,

    Happy New Year everyone. I have some questions here regarding to my project. Please give me some precious comments, thanks a lot.

    Currently I have a project, it is a xy positioning table...I use two dc motors as the actuators of the system and two potentiometer as the feedback sensor. Now I need to build a model for the entire system using Matlab. I am going to create the model by using data driven modeling (using the input output data that I have collected from the open loop testing of my system).

    Now my problem is I am not sure what is the physical quantity that i need to measure to use as the output data? Is it the speed of the dc motor or the position of the dc motor? The input data I think is the normal input voltage. Then what suppose to be the output data? Is the way I am using to collect input output data correct? I can use system identification toolbox to build the model of my system right?

    I am going to build two models for x-axis and y-axis respectlively. Please let me know if my explaination is unclear. Please advice. Thank you very much.

    Regards,
    herher
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,432
    3,360
    You need to measure position. Speed can be determined from consecutive position data.
     
  3. herher

    Thread Starter Member

    Oct 18, 2011
    53
    0
    Hi,

    Thanks for the reply.

    Actually, this is the thing I am confusing. How can I measure the position? Doesn't it if I supply a voltage to my system, let's say 5V the system will keep rotating, then what is the position I suppose to measure?

    Oh ya I forgot to mention, the potentiometer (10-turns) is connected with dc motor via shaft and coupling. The potentiometer is worked with a voltage divider circuit. Hence when the dc motor turns, the potentiometer will rotate and its output will return the signal back to the processor.

    Please advice. Thank you very much.

    Best Regards,
    herher
     
  4. herher

    Thread Starter Member

    Oct 18, 2011
    53
    0
    Hi,

    Is there anyone over here who knows much about MATLAB system identification toolbox? I have some questions regarding to this.

    I will write down the questions if there is any reply.

    Please help. Thank you very much

    Best Regards,
    herher
     
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